Why does addnew fail when I have a checkbox bound to a sql bit column?

steps to recreate the problem:

1 - Create a table in sql with a varchar and a bit column.
2 - Add a couple of records to the table so you can see that the dataform is
actually working
3 - Use the DataFormWizard to create a form bound to that table (On the
'Choose Display Style' page of the wizard select the 'Single Record in
individual controls' raido button)
4 - Set Project Startup Object to the new dataform.
5 - Run project.
6 - Press the 'Load' button on the new dataform.
7 - Press the add button.

I am unable to add new records. the X of x counter indicates a new record
has benn added but I am unable to get to it using the nav buttons.

If I set the databindings-checked property of the checkbox to (none) i am
able to add a new record.